Conventionally, an image forming apparatus has included an actuator for detecting a recording medium. The configuration includes a sensing arm, part of which is located in a conveyance path of a recording medium, and which detects the recording medium by the rotation of the sensing arm according to the conveyance of the recording medium.
The aforementioned actuator detects a recording medium by a sensing arm. The sensing arm needs to be pushed and rotated by a conveyed recording medium. Immediately after the recording medium has passed, the sensing arm needs to be brought to a position in which another recording medium is expected to pass. In addition, the recording medium may be fed backward by users for jam processing. Therefore, it is preferable that the recording medium not be easily interfered with by a sensing lever, and a jammed recording medium be easily removable.
In view of this problem, the conventional technology provides a configuration of a sensing arm including a main arm and an auxiliary arm which is coupled to the main arm and can be rotated only in one direction. In this configuration, the main and auxiliary arms are rotated in a forward direction during normal conveyance. However, when a recording medium is fed backward, only the auxiliary arm is rotated backward to allow the recording medium to be removed. This configuration has a disadvantage in that the sensing arm needs to be formed of a plurality of components, thereby increasing the number of components, the cost, and complicating the structure of the sensing arm itself.
Therefore, there is a need in the art for a sensing arm with a simple configuration in which a recording medium cannot be easily interfered with a sensing arm even when the recording medium is fed backward.